Method of controlling connection establishment in a wireless network

ABSTRACT

Methods of controlling connection establishment to transmit or receive AA/data in a wireless network are disclosed. A method of controlling connection establishment to transmit or receive AA/data in a first device of a wireless network, which includes a coordinator and at least one device, comprises transmitting connection request information required to request connection establishment with a second device and a connection request message which includes capability information of the first device to the second device, and receiving a connection response message from the second device in response to the connection request message. As well as message formats to said methods are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. §371 ofInternational Application No. PCT/KR2007/006506, filed on Dec. 13, 2007,which claims the benefit of earlier filing date and right to priority toKorean Application No. 10-2006-0127375, filed on Dec. 13, 2006.

TECHNICAL FIELD

The present invention relates to a wireless communication system, andmore particularly, to a method of controlling connection establishmentto transmit A/V data in a wireless communication system and a dataformat for the same.

BACKGROUND ART

Recently, Bluetooth, wireless personal area network (WPAN) technologyhas been developed, which allows audio or video data to be exchangedbetween devices by configuring a wireless network between a relativelysmall number of digital devices in limited places such as homes orsmall-scaled companies. WPAN can be used to exchange information betweena relatively small number of digital devices in a relatively closedistance, and enables communication of low power and low cost betweendigital devices.

FIG. 1 illustrates a configuration example of WPAN. As shown in FIG. 1,the WPAN is a network configured between personal devices within alimited place such as home. The network is configured by directcommunication between devices to enable seamless exchange of informationbetween applications. Referring to FIG. 1, the WPAN is comprised of atleast two user devices 11 to 15, wherein one of the user devices isoperated as a coordinator 11. The coordinator 11 serves to provide basictiming of the WPAN and control quality of service (QoS) requirements.Examples of the user devices include a computer, a PDA, a notebook acomputer, a digital TV, a camcorder, a digital camera, a printer, amike, a speaker, a headset, a barcode reader, a display, and cellularphones. All digital devices can be used as the user devices.

To transmit audio and video (A/V) data streams from a source device to asink device under the control of a controller in a wireless networkwhich is previously set, connection control between the source deviceand the sink device is required. Signaling between devices for theconnection control should be simplified if possible, so that delay indisplaying A/V data, which are transmitted from the source device,through the sink device can be reduced.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention is directed to a method ofcontrolling connection establishment to transmit A/V data in a wirelessnetwork and a data format for the same, which substantially obviate oneor more problems due to limitations and disadvantages of the relatedart.

An object of the present invention is to provide a method of simplifyingsignaling for connection establishment between devices to transmit A/Vdata in a wireless network.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, amethod of controlling connection establishment to transmit or receiveA/V data in a first device of a wireless network, which includes acoordinator and at least one device, comprises transmitting a connectionrequest message including connection request information necessary forrequesting connection establishment with a second device and capabilityinformation of the first device to the second device, and receiving aconnection response message from the second device in response to theconnection request message.

In another aspect of the present invention, a method of controllingconnection establishment to transmit A/V data in a source device of awireless network, which includes a coordinator and at least one device,comprises receiving a connection request message including connectionrequest information necessary for requesting connection establishmentand capability information of a sink device from the sink device,performing a bandwidth reservation procedure for allocating channelresources with the coordinator of the wireless network to transmit theA/V data, and transmitting a connection response message to the sinkdevice in response to the connection request message.

In still another aspect of the present invention, a message format for arequest of connection establishment between a source device and a sinkdevice in a wireless network, which includes a coordinator and at leastone device, comprises a connection request information field regionincluding information necessary for requesting connection establishmentwith the source device in the sink device, and a capability informationfield region including information related to capability of the sinkdevice.

In further still another aspect of the present invention, a messageformat structure for a response of connection establishment between asource device and a sink device in a wireless network, which includes acoordinator and at least one device, comprises a connection responseinformation field region including information necessary for respondingto a request of connection establishment with the source device in thesink device, and a data format information field region includinginformation related to capability of the source device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a configuration example of WPAN;

FIG. 2 illustrates a configuration example of WVAN;

FIG. 3 is a flow chart illustrating a procedure according to thepreferred embodiment of the present invention;

FIG. 4 illustrates an example of a data format of CONNECT_INDICATIONmessage used in the preferred embodiment of the present invention;

FIG. 5 illustrates an example of a data format of a connection requestmessage transmitted from AVC layer of a sink device to AVC layer of asource device in accordance with the preferred embodiment of the presentinvention; and

FIG. 6 illustrates an example of a format of a connection responsemessage according to the preferred embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, structures, operations, and other features of the presentinvention will be understood readily by the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Embodiments described hereinafter are examples in whichtechnical features of the present invention are applied to a wirelessvideo area network (WVAN) which is a kind of a wireless private accessnetwork (WPAN). The WVAN is a network which can provide throughput of4.5 Gbps or greater to transmit 1080p A/V streams without compression ina close distance within 10 m by using a frequency band of 60 GHz.

FIG. 2 illustrates a configuration example of WVAN. The WVAN includes atleast two user devices 21 to 25, wherein one of the user devices isoperated as a coordinator 21. The coordinator 21 serves to provide basictiming of the WVAN and control quality of service (QoS) requirements. Inother words, the WVAN supports physical layers, i.e., a high-ratephysical (HRP) layer and a low-rate physical (LRP) layer. The HRP layeris a physical layer which supports a data transmission speed of 1 Gbpsor greater while the LRP layer is a physical layer which supports a datatransmission speed of several Mbps. The HRP layer is highly directional,and is used to transmit isochronous data streams, asynchronous data, MACcommand, and A/V control data through unicast connection. The LRP layersupports a directional or omni-directional mode, and is used to transmita beacon, asynchronous data, and MAC command through unicast orbroadcast.

FIG. 3 is a flow chart illustrating a procedure according to thepreferred embodiment of the present invention, wherein the procedureincludes connection establishment for transmitting A/V data streams froma source device to a sink device in a WVAN which is previously set.Although the sink device is operated as a coordinator of the WVAN in theembodiment of FIG. 3, a separate device may be operated as acoordinator. Each device includes protocol layers such as a physical(PHY) layer, a medium access control (MAC) layer, and an AVC layer. TheAVC layer controls A/V stream connection between the source device andthe sink device by using AVC messages, controls (power on/off,play/stop, etc.) other devices, and controls clock synchronization(pixel clock, audio clock, and synchronization between audio and video).

Referring to FIG. 3, the AVC layer of the sink device receives aCONNECT_INDICATION message from the source device [S31], orspontaneously transmits CONNECT.request primitive to the MAC/PHY layerof the sink device to establish connection with the source device eventhough it does not receive the CONNECT_INDICATION message [S32]. Also,the AVC layer of the sink device receives CONNECT.response primitivefrom the MAC/PHY layer in response to the CONNECT.request primitive[S33]. Moreover, the AVC layer of the sink device transmits a connectionrequest message (CONNECT_REQUEST_FOR_FAST_START) to the AVC layer of thesource device to request connection establishment with the source device[S34].

FIG. 4 illustrates an example of a data format of the CONNECT_INDICATIONmessage. The CONNECT_INDICATION message is transmitted from the sourcedevice to the sink device if the source device desires to transmit audiodata and/or video data (A/V data) to the sink device. In FIG. 4, an‘Opcode’ field represents a type of a message, and a ‘VP’ field is setto ‘1’ if the source device requests a port for video data. The ‘VP’field is set to ‘0’ if not so. An ‘AP’ field is set to ‘1’ if the sourcedevice requests a port for audio data. The ‘AP’ field is set to ‘0’ ifnot so. A PID field is a field which includes port request ID, andincludes different values if the source device requests one sink deviceof a plurality of ports while the PID field is set to ‘0’ if not so.

The connection request message includes information required for arequest of connection establishment with the source device andinformation for indicating capability of the sink device. Since the A/Vdata may include various audio formats and various video formats andsupportable A/V data formats may be varied depending on devices, thesink device transmits its capability information to the source devicewhile requesting connection with the source device.

FIG. 5 illustrates an example of a data format of a connection requestmessage transmitted from the AVC layer of the sink device to the AVClayer of the source device in accordance with the preferred embodimentof the present invention. In FIG. 5, the connection request messageincludes an ‘Opcode’ field representing a type of a correspondingmessage as an operation code, a connection request information fieldregion ‘A’ which includes information required for a request ofconnection establishment with the source device, and a capabilityinformation field region ‘B’ which includes capability information ofthe sink device. The connection request information field region ‘A’includes a PID field, an R field, a VP field, an AP field, and a ‘Destport’ field. The capability information field region ‘B’ includes atleast one ‘Format type’ field and at least one ‘Format data’ field.

The PID field includes port request ID. If the sink device requests thesource device of a plurality of ports, the PID field is set to differentvalues. If the sink device receives the CONNECT_INDICATION message fromthe source device, the PID field is set to a value included in thereceived CONNECT_INDICATION message. If not so, the PID field is set to‘0.’ The R field is a reserved field. The VP field is set to ‘1’ if adestination port is used for video data. The VP field is set to ‘0’ ifnot so. If the sink device receives the CONNECT_INDICATION message fromthe source device, the VP field is set to a value included in thereceived CONNECT_INDICATION message. The AP field is set to ‘1’ if thedestination port is used for audio data. The AP field is set to ‘0’ ifnot so. If the sink device receives the CONNECT_INDICATION message fromthe source device, the AP field is set to a value included in thereceived CONNECT_INDICATION message. The ‘Dest Port’ field is a fieldwhich indicates a destination port, and includes port information of thesink device.

The ‘Format type’ field includes information of a type of data includedin the ‘Format data’ field. In FIG. 5, ‘EDID,’ ‘Audio Info,’ and‘Lipsync’ are exemplarily illustrated as examples of the ‘Format type,’while ‘EDID data,’ ‘Audio_INFO data,’ and ‘Lipsync data’ are exemplarilyillustrated as ‘Format data’ of the respective examples of the ‘Formattype.’ Since the ‘Format data’ and the ‘Format type’ are exemplarilyillustrated in FIG. 5, the connection request message may includeinformation related to a data format of random video data and/or audiodata supported by the sink device.

The AVC layer of the source device transfers a CONNECT.request primitiveto the MAC/PHY layer to establish connection with the sink device, andreceives CONNECT.response primitive from the MAC/PHY layer in responseto the CONNECT.request primitive [S36].

The AVC layer of the source device determines a data format of A/V datato be transmitted to the sink device, based on capability information ofthe sink device, which is included in the connection request messagereceived from the sink device. At this time, the AVC layer of the sourcedevice determines a data format of A/V data to be transmitted within therange of capability of the sink device. In other words, the sourcedevice should transmit audio and video formats supported by the sinkdevice. If the capacity of A/V data of the source device exceedscapability of the sink device, the source device can change the formatof the A/V data to adapt to capability of the sink device.

The AVC layer of the source device transmits a BW-RESERVATION.reqprimitive to the MAC/PHY layer to command the MAC/PHY layer to performreservation of a bandwidth based on data format information of thedetermined A/V data [S37]. The BW-RESERVATION.req primitive includesinformation of the calculated data rate.

A MAC layer of the source device performs a bandwidth reservationprocedure together with a MAC layer of the coordinator [S38]. The sourcedevice is allocated with radio resources for transmission of the A/Vdata from the coordinator by the bandwidth reservation procedure. If thebandwidth reservation procedure successfully ends, the MAC layer of thesource device transfers the BW-RESERVATION.rsp primitive to the AVClayer to indicate that the bandwidth has been successfully allocated[S39].

The AVC layer of the source device transmits a connection responsemessage (CONNECT_RESPONSE_FOR_FAST_START) to the AVC layer of the sinkdevice [S40]. The connection response message includes connectionresponse information required for a response to the connection requestmessage and capability information of the source device. The connectionresponse information includes result information of connectionestablishment and port information of the source device, and thecapability information of the source device includes data formatinformation of A/V data that can be supported by the source device.

FIG. 6 illustrates an example of a format of the connection responsemessage. In FIG. 6, the connection response message includes an ‘Opcode’field, a connection response information field region ‘C’, and a dataformat information field region ‘D’. The connection response informationfield region ‘C’ includes a ‘Result Code’ field, an R field, a VP field,an AP field, a ‘Dest Port’ field, and a ‘Src Port’ field. The dataformation information field region ‘D’ includes at least one ‘Formattype’ field and at least one ‘Format data’ field as data formatinformation of A/V data that can be supported by the source device.

The VP field, the AP field and the ‘Dest Port’ field are the same asthose described with reference to FIG. 5. The ‘Result Code’ field is afield which includes the result of connection request, and includesinformation as to whether connection request has been accepted orrejected. The ‘Src Port’ field is a field which includes portinformation of the source device. The ‘Format type’ field represents atype of information included in the ‘Format data’ field. The ‘Formatdata’ field includes information such as a data format of A/V data thatcan be transmitted from the source device.

The source device transmits A/V streams to the sink device throughchannel resources reserved by the bandwidth reservation procedure [S41].In the embodiment of FIG. 3, the bandwidth reservation procedure (S37 toS39) and the step (S40) of transmitting the connection response messagemay be performed by varying their order. In other words, the bandwidthreservation procedure may be performed after the source device transmitsthe connection response message to the sink device.

Meanwhile, unlike the embodiment of FIG. 3, another way of connectioncontrol may be considered, in which the source device transmits aconnection request message to the sink device to initiate a connectioncontrol procedure, and the sink device transmits a connection responsemessage to the source device. In this case, the connection requestmessage includes information for a request of connection establishmentand capability information of the source device, while the connectionresponse message includes connection response information and capabilityinformation of the sink device. With respect to the other procedures andtheir detailed description, the embodiment of FIG. 3 can be referred to.

Terminologies used herein may be replaced with other terminologies. Forexample, the device may be replaced with a user device (or apparatus) orstation, the coordinator may be replaced with a coordinating apparatus(or control apparatus), a coordinating device (or control device), acoordinating station (or control station), or piconet coordinator (PNC).Also, although it has been described in the aforementioned embodimentsthat the technical features of the present invention have been appliedto the WVAN, the technical features of the present invention can beapplied to a peer-to-peer communication system or other wireless networksystem.

The aforementioned embodiments are achieved by combination of structuralelements and features of the present invention in a predetermined type.Each of the structural elements or features should be consideredselectively unless specified separately. Each of the structural elementsor features may be carried out without being combined with otherstructural elements or features. Also, some structural elements and/orfeatures may be combined with one another to constitute the embodimentsof the present invention. The order of operations described in theembodiments of the present invention may be changed. Some structuralelements or features of one embodiment may be included in anotherembodiment, or may be replaced with corresponding structural elements orfeatures of another embodiment. Moreover, it will be apparent that someclaims referring to specific claims may be combined with another claimsreferring to the other claims other than the specific claims toconstitute the embodiment or add new claims by means of amendment afterthe application is filed.

The embodiments according to the present invention may be implemented byvarious means, for example, hardware, firmware, software, or theircombination. If the embodiment according to the present invention isimplemented by hardware, it may be implemented by one or moreapplication specific integrated circuits (ASICs), digital signalprocessors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

If the embodiment according to the present invention is implemented byfirmware or software, it may be implemented by a type of a module, aprocedure, or a function, which performs functions or operationsdescribed as above. A software code may be stored in a memory unit andthen may be driven by a processor. The memory unit may be located insideor outside the processor to transmit and receive data to and from theprocessor through various means which are well known.

According to the present invention, signaling for establishingconnection between devices to transmit A/V data in a wireless networkcan be simplified.

It will be apparent to those skilled in the art that the presentinvention can be embodied in other specific forms without departing fromthe spirit and essential characteristics of the invention. Thus, theabove embodiments are to be considered in all respects as illustrativeand not restrictive. The scope of the invention should be determined byreasonable interpretation of the appended claims and all change whichcomes within the equivalent scope of the invention are included in thescope of the invention.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a wireless network system.

1. A method of controlling connection establishment in order to receiveaudio/video (A/V) data in a sink device of a wireless network includinga coordinator and at least one device, the method comprising:transmitting a connection request message to a source device to requesta connection; and receiving a connection response message from thesource device in response to the connection request message, wherein theconnection response message comprises a result of the connectionrequest, wherein the connection request message comprises connectionrequest information together with capability information of the sinkdevice, wherein the connection request information comprises portinformation that indicates a sink port via which the A/V data is to bereceived, wherein the capability information comprises a format datafield and a format type field, wherein the format data field includesformat data of the A/V data supportable by the sink device, and whereinthe format type field includes a type of the format data.
 2. The methodof claim 1, wherein the connection response message further comprisesport information of the source device.
 3. The method of claim 1, furthercomprising: performing a bandwidth reservation procedure for allocatingchannel resources with the coordinator of the wireless network; andreceiving the A/V data from the source device by using the channelresources allocated from the coordinator.
 4. The method of claim 2,wherein the connection response message further comprises data formatinformation related to A/V data that can be supported by the sourcedevice.
 5. The method of claim 4, wherein the connection responsemessage further comprises type information of the data formatinformation.
 6. The method of claim 1, wherein the connection requestmessage further comprises a VP field for indicating whether the sinkport is to be used for video data and an AP field for indicating whetherthe sink port is to be used for audio data.
 7. A sink device forcontrolling connection establishment in order to receive audio/video(A/V) data in a wireless network which includes a coordinator and atleast one device, the sink device configured to: transmit a connectionrequest message to a source device to request a connection; and receivea connection response message from the source device in response to theconnection request message, wherein the connection response messagecomprises a result of the connection request, wherein the connectionrequest message comprises connection request information together withcapability information of the sink device, wherein the connectionrequest information comprises port information that indicates a sinkport via which the A/V data is to be received, wherein the capabilityinformation comprises a format data field and a format type field,wherein the format data field includes format data of the A/V datasupportable by the sink device and wherein the format type fieldincludes a type of the format data.
 8. The sink device of claim 7,wherein the connection response message further comprises portinformation of the source device.
 9. The sink device of claim 7, whereinthe sink device is further configured to: perform a bandwidthreservation procedure for allocating channel resources with thecoordinator of the wireless network; and receive the A/V data from thesource device by using the channel resources allocated from thecoordinator.
 10. The sink device of claim 8, wherein the connectionresponse message further comprises data format information related toA/V data that can be supported by the source device.
 11. The sink deviceof claim 9, wherein the connection response message further comprisestype information of the data format information.
 12. The sink device ofclaim 7, wherein the connection request message further comprises a VPfield for indicating whether the sink port is to be used for video dataand an AP field for indicating whether the sink port is to be used foraudio data.